1. Field of the Invention
This invention relates to an amorphous semiconductor solar battery using an amorphous silicon, germanium or the like.
2. Description of the Prior Art
In prior art solar batteries, as shown in FIG. 1, for instance, a glass substrate a is coated, with a transparent electrode b, an amorphous silicon layer c comprising a p layer c.sub.1, an i layer c.sub.2 and an n layer c.sub.3 (or n-i-p layers) and a rear surface electrode d. This type of solar battery is advantageous in that the glass substrate is low in cost and easily provides a flat front surface thereof which is transparent so that light rays enter the battery from the glass substrate side thereof. Additionally the glass substrate is an insulator, so that it is possible to form plural battery elements thereon and connect them in series or parallel. However, the solar battery of this type is disadvantageous in that the conversion efficiency thereof is only about 2%, and is lower than that of a recently developed so called reverse type p-i-n solar battery in which a stainless steel substrate is coated with an amorphous silicon layer composed of p-i-n layers and a transparent electrode or of a conventional solar battery in which a glass substrate is coated with a transparent electrode, a p layer of amorphous silicon carbide including carbon, i and n layers of amorphous silicon, and a rear surface electrode.
In a conventional solar battery having the foregoing construction, it has been usual to use a transparent electrode of the type used for a liquid crystal indication element or the like. In such a device the sheet resistance thereof is to be as small as possible and at the same time the solar light transmission rate thereof is to be as high as possible. The transparent electrode thereof is so clear that the other side of the electrode can be seen clearly therethrough with the naked eye, and the average grain diameter thereof is less than about 0.05 .mu.m.